Effect of Weather Parameters on of Pests and Diseases in Groundnut and Castor in Salem District of Tamil Nadu, India

Abstract

The roving survey on the incidence of pests and diseases in groundnut and castor was conducted from August, 2020 to March 2021 in Salem district at fortnight intervals revealed that, in groundnut , leaffolder (20.38%), cutworms S. litura (1.63/20 pls), thrips (10.69/20 pls), leaf spot (15.25%) and root rot (6.31%) , similarly in castor pests, whiteflies (23.06/20 pls), A. janata (8.38/20 pls), S. litura (10.19/ 20 pls), thrips (11.63 / 20 pls), C. punctiferalis (7.25/20 pls), alternaria blight (17.56%) and botrytis rot (4.19%) were found feeding /infecting on different parts of the crops. The correlation with weather parameters indicated, positive correlation of rainfall, relative humidity and wind speed on incidence of leaffolder (0.47998, 0.311421 and 0.339961) but rainfall and relative humidity increased root rot (0.433059 and 0.393255) whereas, maximum temperature influenced high infection of leafspot (0.67911) in groundnut. The whiteflies incidence in castor was positively correlated with (0.490967) and rainfall (0.389125) whereas, lepidopteran pests by relative humidity (0.61212) and rainfall (0.49415). The thrips and botrytis rot were influenced by relative humidity and rainfall rot (0.65914 and 0.77965, 0.57456 and 0.82709). But natural enemies in groundnut and castor had non-significant correlation with weather parameters.